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Journal Articles

Unified mercury radioactivity monitoring system at J-PARC and its operation experiences

Harada, Masahide; Sekijima, Mitsuaki*; Morikawa, Noriyuki*; Masuda, Shiho; Kinoshita, Hidetaka; Sakai, Kenji; Kai, Tetsuya; Kasugai, Yoshimi; Muto, Giichi*; Suzuki, Akio*; et al.

JPS Conference Proceedings (Internet), 33, p.011099_1 - 011099_6, 2021/03

In MLF at J-PARC, a unified mercury radioactivity monitor (UHAM) is installed to find an indication of failure of the mercury target and loop system by detecting radioactive materials leaked from the system with a $$gamma$$-ray energy analysis with Germanium semi-conductor detectors (Ge detectors). It is composed of three units of sampling port and radiation monitors: (1) HAM for interstitial helium gas layer between the mercury vessel and surrounding water shroud of the mercury target, (2) CAM for atmosphere in the hot cell where the target loop is operated and (3) VAM for helium gas in the helium vessel where the target vessel is installed. Once any leakages of radioactive materials are detected, an alarm signal is issued immediately to the accelerator control system to stop beam operation. Software and hardware have been upgraded yearly. For example, two Ge detectors are used for HAM for redundancy, NaI Scintillation detectors are also used as supplemental for the Ge detector to keep availability of the system for high counting rate event. In April 2015, the UHAM activated when a small water coolant leakage from the water shroud of the mercury target occurred. VAM detected an abnormal increase of the counting rate in the helium vessel. It was also indicated that the measured radioactive nuclides were generated from the activation of the coolant (water) in the water shroud and not from the mercury.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:30 Percentile:96.87(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Comparative study on annual $$^{137}$$Cs discharge rates after the Fukushima Dai-ichi Nuclear Power Plant accident from two distinct watershed simulation models

Kitamura, Akihiro; Imaizumi, Yoshitaka*; Yamaguchi, Masaaki; Yui, Mikazu; Suzuki, Noriyuki*; Hayashi, Seiji*

Kankyo Hoshano Josen Gakkai-Shi, 2(3), p.185 - 192, 2014/09

Annual discharge rates of radioactive cesium through selected rivers due to the Fukushima Dai-ichi Nuclear Power Plant accident were simulated by two different watershed models. One is the Soil and Cesium Transport, SACT, model which was developed by Japan Atomic Energy Agency and the other one is the Grid-Catchment Integrated Modeling System, G-CIEMS, which was developed by National Institute of Environmental Studies. We choose the Abukuma, the Ukedo, and the Niida rivers for the present study. Comparative results showed that while components and assumptions adopted in two models differ, both methods predicted the same order of magnitude estimates.

Journal Articles

Static tensile deformation behavior of a lean duplex stainless steel studied by in situ neutron diffraction and synchrotron radiation white X-rays

Tsuchida, Noriyuki*; Kawahata, Takuji*; Ishimaru, Eiichiro*; Takahashi, Akihiko*; Suzuki, Hiroshi; Shobu, Takahisa

ISIJ International, 53(7), p.1260 - 1267, 2013/07

 Times Cited Count:23 Percentile:73.92(Metallurgy & Metallurgical Engineering)

To investigate the tensile deformation behavior of a lean duplex stainless steel (S32101) from the viewpoints of plastic deformability among phases or grains, we performed static tensile tests, in situ neutron diffraction, and white X-ray diffraction experiments at room temperature. From the experimental results of synchrotron radiation white X-ray diffraction experiments, the hard phase of S32101 was changed from the ferrite phase to austenite one during tensile deformation. This led to a larger stress partitioning between the phases at the latter stage of deformation. From the experimental results of in situ neutron diffraction, it was found that the stress partitioning of the $$gamma$$ phase in the S32101 was the largest among the present results. Therefore, the larger work hardening rate of S32101 can be explained by the large stress partitioning of the $$gamma$$ phase, that between $$gamma$$ and $$alpha$$ phases and $$gamma$$ volume fraction.

Journal Articles

Current status of JMTR

Ishihara, Masahiro; Kimura, Nobuaki; Takemoto, Noriyuki; Ooka, Makoto; Kaminaga, Masanori; Kusunoki, Tsuyoshi; Komori, Yoshihiro; Suzuki, Masahide

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 7 Pages, 2012/10

The JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR, fusion reactor as well as for RI productions. The refurbishment of the JMTR was started from the beginning of JFY 2007, and finished in March 2011 as planned schedule. Unfortunately, at the end of the JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure, ground sinking around the reactor building. Consequently, the restart will delay from June 2011. Now, the safety evaluation of the facility after the earthquake disaster is being carried out aiming at the restart of the JMTR. The renewed JMTR will be started from JFY 2012 and operated for a period of about 20 years until around JFY 2030. The usability improvement of the JMTR is also discussed with users as the preparations for re-operation.

Journal Articles

Nuclear human resource development using JMTR and related facilities as advanced research infrastructures

Takemoto, Noriyuki; Hori, Naohiko; Nakagawa, Shigeaki; Ishitsuka, Etsuo; Kaminaga, Masanori; Nurzhan, S.*; Takibayev. N.*; Aliyev, B.*; Suzuki, Masahide

Proceedings of International Conference of Young Scientists and Specialists; Current Issues on the Peaceful Use of Atomic Energy (Internet), p.17 - 27, 2012/06

The JMTR is expected to be a key infrastructure with related facilities to contribute the nuclear Human Resource Development (HRD) by a research and On-the-Job-Training (OJT) in order to support global expansion of nuclear power industry. The training program for Asian young researchers and engineers were started from JFY 2011 in JAEA, and 10 trainees from Kazakhstan and Thailand had studied in JFY 2011. In addition, the training course was newly established for domestic students and young engineers from JFY 2010 to JFY 2012, and 45 domestic students and engineers were studied in the course from JFY 2010 to JFY 2011.

Journal Articles

Training program for students and young engineers in JMTR

Takemoto, Noriyuki; Izumo, Hironobu; Hori, Naohiko; Ishitsuka, Etsuo; Suzuki, Masahide

JAEA-Conf 2011-003, p.265 - 269, 2012/03

The JMTR is expected to be a key infrastructure to contribute the nuclear Human Resource Development (HRD) by a research and On-Job-Training (OJT) in order to support global expansion of nuclear power industry. The training program for Asian young researchers and engineers were started from JFY 2011 in JAEA, and ten trainees from Kazakhstan and Thailand had attended in this program in JFY 2011. In addition, in the nuclear HRD initiative program sponsored by the MEXT, the training course was newly established for domestic students and young engineers from JFY 2010 to JFY 2012. In this course, basic understanding on irradiation test and post irradiation examination is aimed to achieve by overall and practical training such as the neutronic/thermal designs of irradiation capsule, post irradiation examination, measurement and evaluation of neutron fluence, etc. using the JMTR and the related facilities. The 1st training course was held with 10 trainees in JFY 2010. The 2nd and 3rd training courses were also held with 19 trainees and 16 trainees in JFY 2011. From JFY 2012, two courses will be held in every year, and 20 trainees will be accepted in each course.

Journal Articles

Real time simulator for material testing reactor

Takemoto, Noriyuki; Imaizumi, Tomomi; Izumo, Hironobu; Hori, Naohiko; Suzuki, Masahide; Ishitsuka, Tatsuo*; Tamura, Kazuo*

JAEA-Conf 2011-003, p.271 - 275, 2012/03

Japan Atomic Energy Agency (JAEA) is now developing a real time simulator for a material testing reactor in order to utilize a nuclear human resource development and promotion of partnership with developing countries which have a plan to introduce nuclear power plant and/or experimental research reactor. The simulator is scheduled to be operated in JFY2012. The simulator is based on Japan Materials Testing Reactor (JMTR), and treats most of JMTR, e.g. reactor, primary cooling system, secondary cooling system, emergency cooling system, instrumentation and control system, safety and protection systems and electricity system. It simulates normal operation condition, transient operation condition such as excess reactivity addition due to testing material insertion and condition of the LOCA. Moreover, it simulates an irradiation experiment using irradiation equipments such as material testing under BWR condition. The simulator is composed of a computer system, a console for reactor control, process control, irradiation equipments, and an instructor and large-size displays. The simulator has the control functions, such as load and store of initial conditions, selection of core conditions, control of execution (run/freeze/fast/slow), save of backtrack snapshots at regular intervals, etc. in order to increase education effects. Furthermore, it has actions, such as malfunctions, remote functions, global component failures, annunciator master control, etc.

Journal Articles

Initiation of systems radiation biology in Japan

Sakashita, Tetsuya; Suzuki, Michiyo; Ouchi, Noriyuki; Ban, Nobuhiko*

Hoshasen Seibutsu Kenkyu, 45(4), p.379 - 395, 2010/12

Recently, systems radiation biology (SRB) has been studied and developed in Europe and USA. Also, Japanese researchers in radiation biology are interested in this research field, gradually. In this review, four scientists shortly review SRB in each stand points.

Journal Articles

Development of an international matrix-solver prediction system on a French-Japanese international grid computing environment

Suzuki, Yoshio; Kushida, Noriyuki; Tatekawa, Takayuki; Teshima, Naoya; Caniou, Y.*; Guivarch, R.*; Dayde, M.*; Ramet, P.*

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 6 Pages, 2010/10

The "Research and Development of International Matrix-Solver Prediction System (REDIMPS)" project, which is founded by the Strategic Japanese-French Cooperative Program on "Information and Communications Technology including Computer Science" with CNRS and JST, aims at improving the "Test for Large System of Equations (TLSE)" sparse linear algebra expert system by establishing an international grid computing environment between Japan and France. Here, we have established the interoperable environment between French and Japanese grid middleware (DIET and AEGIS), and have confirmed that TLSE can rely on this French and Japanese interoperable environment for researchers to select a matrix-solver suitable to their each application program. By this study, we proposed to the French and Japanese researchers the environment in which they can obtain useful information for the improvement of their application program.

Journal Articles

Interoperation between Atomic Energy Grid Infrastructure (AEGIS) and other grids

Suzuki, Yoshio; Kushida, Noriyuki; Teshima, Naoya; Nakajima, Kohei; Nishida, Akemi; Nakajima, Norihiro

High Performance Computing on Vector Systems 2008, p.65 - 77, 2009/00

Center for computational science and e-systems, Japan Atomic Energy Agency (CCSE/JAEA) has been carrying out R&Ds of grid computing technology since FY1995 aiming at establishing an infrastructure for the computational science research. One of them is R&D of IT-Based Laboratory (ITBL) infrastructure. The ITBL project is a national project placed as one of the e-Japan Priority Policy Program to realize the e-Japan Strategy. By succeeding the technology of ITBL infrastructure, CCSE is carrying out R&D of Atomic Energy Grid Infrastructure (AEGIS) to construct an intelligent infrastructure for the atomic energy research. CCSE has been carrying out international cooperation researches in various fields to advance computer science and to expand AEGIS grid computing environment. To achieve this, we have developed the system to construct interoperable environments between AEGIS and other grid middleware.

Journal Articles

Development of cognitive methodology based data analysis system

Kino, Chiaki; Suzuki, Yoshio; Kushida, Noriyuki; Nishida, Akemi; Hayashi, Sachiko; Nakajima, Norihiro

High Performance Computing on Vector Systems 2008, p.89 - 97, 2009/00

In a field of research for nuclear power station, large and complex data analysis is an important issue. To overcome this issue, we have been developing Cognitive methodology based Data Analysis System (CDAS) in order to support researchers to analyze large and complex data. In the present study, we cleared up a structure of data analysis consisting of analysis target, evaluation index and judgment criteria. Additionally, we proposed some computational technologies to actualize CDAS. We have applied the system to the virtual plant vibration simulator and confirmed the implementability of this system.

Journal Articles

Development of three-dimensional virtual plant vibration simulator on grid computing environment ITBL-IS/AEGIS

Suzuki, Yoshio; Nishida, Akemi; Araya, Fumimasa; Kushida, Noriyuki; Akutsu, Taku; Teshima, Naoya; Nakajima, Kohei; Kondo, Makoto; Hayashi, Sachiko; Aoyagi, Tetsuo; et al.

Journal of Power and Energy Systems (Internet), 3(1), p.60 - 71, 2009/00

Center for computational science and e-systems of Japan Atomic Energy Agency is carrying out R&D in the area of extra large-scale simulation technologies for solving nuclear plant structures in its entirety. Specifically, we focus on establishing a virtual plant vibration simulator on inter-connected supercomputers intended for seismic response analysis of a whole nuclear plant. The simulation of a whole plant is a very difficult task because an extremely large dataset must be processed. To overcome this difficulty, we have proposed and implemented a necessary simulation framework and computing platform. The computing platform enables an extra large-scale whole nuclear plant simulation to be carried out on a grid computing platform ITBL-IS and AEGIS. The simulation framework based on the computing platform has been applied to a linear elastic analysis of the reactor pressure vessel and cooling systems of the nuclear research facility, HTTR.

Journal Articles

A Large scale simulation for impact and blast loading issues

Nakajima, Norihiro; Araya, Fumimasa; Nishida, Akemi; Suzuki, Yoshio; Ida, Masato; Yamada, Tomonori; Kushida, Noriyuki; Kim, G.; Kino, Chiaki; Takemiya, Hiroshi

Proceedings of International Symposium on Structures under Earthquake, Impact, and Blast Loading 2008, p.119 - 123, 2008/10

Japan is so said an energy consumption country of the fourth place world, but the energy resources such as petroleum, the natural gas are poor and depend on import for the most, and stable supply becomes a big problem. For the greenhouse gas restraint, the promotion of the energy saving is featured. A nuclear power plant for commerce in Japan has been started in 1966. The supply occupies about 30 percent of the now Japanese electricity generating. Due to the nature of Japan, earthquake proof is an important subject for social infrastructure operation. To encourage its proofing, many approaches have been applied into many infrastructures, not only computational approach. A computational science approach for earthquake proof is suggested with FIESTA(Finite Element Structural analysis for Assembly), a large scale simulation. A methodology is discussed from the point of view of impact and blast loadings. Examples of loadings in the nuclear engineering are introduced.

Journal Articles

Concept design of cognitive methodology based data analysis system; Application to seismic analysis using finite element method

Kino, Chiaki; Suzuki, Yoshio; Nishida, Akemi; Kushida, Noriyuki; Hayashi, Sachiko; Nakajima, Norihiro

Nihon Keisan Kogakkai Rombunshu (Internet), 2008(18), 8 Pages, 2008/07

We have conducted research and development of the Cognitive methodology based Data Analysis System (CDAS) which supports researchers to analyze large scale data efficiently and comprehensively. Traditionally, much of data analysis process has been carried out by humans. However, when the scale of data is extremely large, data analysis is beyond the recognition capability of humans. The basic idea of CDAS is that computers execute data analysis instead of humans. In the present study, we showed three necessary functions (Verification and Validation: VV, Data Diagnosis: DD and Synthesis) for the design of CDAS. VV and DD functions are executed on gird computing environment and findings output from these functions are integrated on Synthesis functions. Finally CDAS displayed only useful information to human. We have applied the system to the virtual plant vibration simulator and succeeded in analyzing large scale data reaching to 1TB thoroughly for the first time.

Journal Articles

Real space simulation with reality modeling for vibration table by an assembly structural analysis

Nakajima, Norihiro; Araya, Fumimasa; Nishida, Akemi; Suzuki, Yoshio; Kushida, Noriyuki; Yamada, Tomonori

Dai-57-Kai Riron Oyo Rikigaku Koenkai Koen Rombunshu, p.33 - 35, 2008/06

It has been disciplined to realize a simulation space, which can emulate real world in digital space, such as so named either virtual reality or virtual facility. In this paper, it is realized an assembly structural analysis for supplying one of the methodology to reproduce facilities in digital space. The first attempt of the assembly structural analysis is accomplished by finite element analysis by integrating parts of facilities. Since the assembly structural analysis requests massive calculation, grid computing was applied for the computational resource.

Journal Articles

Toward an international sparse linear algebra expert system by interconnecting the ITBL Computational Grid with the Grid-TLSE platform

Kushida, Noriyuki; Suzuki, Yoshio; Teshima, Naoya; Nakajima, Norihiro; Caniou, Y.*; Dayd$'e$, M.*; Ramet, P.*

Proceedings of 8th International Meeting on High Performance Computing for Computational Science (VECPAR '08) (CD-ROM), p.424 - 429, 2008/06

In the present paper, the methodology of interoperability between ITBL and Grid-TLSE is described. Grid-TLSE is an expert website to provides user assistance in choosing the right solver for its problems and appropriate values for the control parameters of the selected solve. The time to solution of linear equation solver strongly depends on the type of problem, the selected algorithm, its implementation and the target computer architecture. Grid-TLSE uses the Diet middle ware to distribute computing tasks over the Grid. Therefore, extending the variety of computer architecture by Grid middle ware interoperability between Diet and ITBL has a beneficial impact to the expert system. To show the feasibility of the methodology, job transfering program as a special service of Diet was developed.

Journal Articles

Development of three-dimensional virtual plant vibration simulator on grid computing environment ITBL-IS/AEGIS

Suzuki, Yoshio; Nakajima, Norihiro; Araya, Fumimasa; Hazama, Osamu; Nishida, Akemi; Kushida, Noriyuki; Akutsu, Taku; Teshima, Naoya; Nakajima, Kohei; Kondo, Makoto; et al.

Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 9 Pages, 2008/05

Journal Articles

Research and development of fusion grid infrastructure based on Atomic Energy Grid InfraStructure (AEGIS)

Suzuki, Yoshio; Nakajima, Kohei; Kushida, Noriyuki; Kino, Chiaki; Aoyagi, Tetsuo; Nakajima, Norihiro; Iba, Katsuyuki*; Hayashi, Nobuhiko; Ozeki, Takahisa; Totsuka, Toshiyuki; et al.

Fusion Engineering and Design, 83(2-3), p.511 - 515, 2008/04

 Times Cited Count:3 Percentile:23.58(Nuclear Science & Technology)

In collaboration with the Naka Fusion Institute of Japan Atomic Energy Agency (NFI/JAEA) and the National Institute for Fusion Science of National Institute of Natural Science (NIFS/NINS), Center for Computational Science and E-systems of Japan Atomic Energy Agency (CCSE/JAEA) aims at establishing an integrated framework for experiments and analyses in nuclear fusion research based on the Atomic Energy Grid InfraStructure (AEGIS). AEGIS has been being developed by CCSE/JAEA aiming at providing the infrastructure that enables atomic energy researchers in remote locations to carry out R&D efficiently and collaboratively through the Internet. Toward establishing the integrated framework, we have been applying AEGIS to pre-existing three systems.

Journal Articles

Integrated framework for simulating behaviors of nuclear power plants under earthquakes

Hazama, Osamu; Kushida, Noriyuki; Matsubara, Hitoshi; Nishida, Akemi; Suzuki, Yoshio; Araya, Fumimasa; Aoyagi, Tetsuo; Nakajima, Norihiro; Kondo, Makoto

Proceedings of 9th MpCCI User Forum, p.118 - 124, 2008/00

In order to safely and stably supply energy by nuclear means, structural integrity and design standards of the plant including factors such as aging must be confirmed, and its future conditions must be predicted with high reliability. Although full-scale experimentations are favorable for acquiring necessary information and carrying out investigative studies of the nuclear structures, such experiments are for most cases physically and financially impossible. Our objective is to establish an integrated full-scale simulation framework for simulating and quantitatively investing the vibration behavior of nuclear power plant equipments under earthquakes.

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